1. Field of the Invention
Embodiments of the present invention relate to a control apparatus for an internal combustion engine comprising a motor which drives a water pump, and a motor which drives an oil pump.
2. Description of the Related Art
Conventionally, an oil pump is used as a device for feeding a lubrication oil (engine oil) into an oil passage (oil path) formed in an internal combustion engine. Generally, the oil pump is driven by a crankshaft. Such an oil pump is referred to as a “mechanical oil pump.” On the other hand, an oil pump is known which is driven by a motor such as a DC motor. Such an oil pump is referred to as an “electric motor driven oil pump.”
The electric motor driven oil pump does not need a structure which connects the crankshaft with the oil pump, unlike the mechanical oil pump. Therefore, the electric motor driven oil pump can reduce friction in the engine. On the other hand, however, the electric motor driven oil pump cannot feed the lubrication oil to the oil passage if it is malfunctioning, and thus, the sliding portions of the internal combustion engine may seize.
An apparatus (hereinafter, referred to as a “conventional apparatus”) disclosed in Japanese Laid Open Patent Application No. 2004-285974 (especially, claim 7, and paragraph 0031) is applied to an internal combustion engine comprising a mechanical oil pump and an electric motor driven oil pump, and is configured to have the mechanical oil pump operate when the electric motor driven oil pump malfunctions.
According to the conventional apparatus, the lubrication oil can be fed to the oil passage even when the electric motor driven oil pump malfunctions. As a result, seizing of the sliding portions of the internal combustion engine may be avoided, when the electric motor driven oil pump malfunctions.